Page 117 - Materials Chemistry, Second Edition

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88 Waste Management Practices: Municipal, Hazardous, and Industrial

TABLE 4.19
Typical Values for Inert Residue and Energy Content of Residential MSW
a
Inert Residue (%) Energy Content (kJ/kg) Energy Content (Btu/lb)
Component Range Range Range
Organic
Food wastes 2–8 3,350–6,700 1,500–3,000
Paper 4–8 11,200–18,000 5,000–8,000
Cardboard 3–6 13,400–16,800 6,000–7,500
Plastics 6–20 26,800–35,750 12,000–16,000
Textiles 2–4 14,500–17,900 6,500–8,000
Rubber 8–20 20,125–26,800 9,000–12,000
Leather 8–20 14,500–19,000 6,500–8,500
Yard wastes 2–6 2,225–17,900 1,000–8,000
Wood 0.6–2 16,770–19,000 7,500–8,500
Misc. organics — — —
Inorganic
Glass 96–99 110–225 50–100
Tin cans 96–99 225–1100 100–500
Aluminum 90–99 — —
Other metal 94–99 225–1120 100–500
Dirt, ashes. 60–80 2230–11,175 1,000–5,000
Municipal solid wastes 8950–13,400 4,000–6,000
a After complete combustion.
Adapted from Tchobanoglous, G. et al., Integrated Solid Waste Management: Engineering Principles and Management
Issues, McGraw-Hill, New York, 1993. Data reproduced with kind permission of the McGraw-Hill Companies, Inc.; Kaiser,
E.R., Proceedings of the National Incinerator Conference, ASME, New York, 1969. Data reproduced with kind permission
of the American Society of Mechanical Engineers.

Fusion temperatures are often measured under both reducing and oxidizing conditions. Typical
o
o
fusion temperatures for clinker formation from MSW range from 1100 to 1200 C (2000 to 2200 F)
(Tchobanoglous et al., 1993).
4.5.5 CONTENT OF NUTRIENTS AND OTHER SUBSTRATES
In applications where the organic fraction of MSW is used as feedstock for compost or biological
conversion into methane and ethanol, information on the essential nutrients in the waste materials
is important. Both composting and biogas production are carried out by diverse consortia of het-
erotrophic microorganisms. Therefore, the microbial nutrient balance of the MSW should be
assessed to allow for maximal conversion for final uses. The composition of essential nutrients and
elements in the organic fraction of MSW is shown in Table 4.20. Nitrogen content, both as nitrate
and ammonium, is highest in food and yard wastes by virtue of their higher protein contents (see
below). Sulfur, potassium, calcium, and magnesium are also markedly higher in food and yard
waste.
The organic fraction of most MSW (i.e., food waste, yard waste, paper products, textiles) can
be classified according to their relative degree of biodegradability as follows:

● Sugars
● Starches and organic acids
● Proteins and amino acids